Valve mechanism of internalcombustion engines



April 2, 1946. E. P. PAXMAN VALVE MECHANISM OF INTERNAL-COMBUSTION ENGINES 'Filed July '14, 1945 'njvenlor LW Attorneys Patented Apr. 2, 1946 VALVE MECHANISM 'OF IN TERNAL- COMBUSTION ENGINES Edward Philip Paxman, Colchester, England Application July 14, 1943, Serial No. 494,707 In Great Britain April 9, 1942 2 Claims;

. This investigation relates'to internal combustion engines and has for its object to provide improved means for housing the push rods through which the valves are operated from rocking arms or levers actuated by a cam shaft the invention being designed to avoid the difliculties normally experienced in accurately aligning the apertures in the cylinder block and cam box through which the push rod would normally pass between the rocker arm and the tappet lever.

According, to the invention a push rod tube adapted to connect a valve housing or cylinder block with a cam box in an internal combustion engine is constituted by a, flexible and longitudinally resilient sleeve detachably mounted and of such dimensions that the push rod passes freely through it.

According to the preferred form of the invention means for housing a valve operating push rod in an internal combustion engine are provided comprising a flexible and resilient sleeve of such dimensions that the push rod passes freely through it and formed at its ends to make fluid tight engagement with apertures in a cam housing and a valve housing, cylinder block or cylinder head. Other features of the preferred form of construction will be described hereinafter.

Reference will now be made to the accompanying drawing in which:

Fig. 1 is a diagram showing the parts of an internal combustion engine to which the invention is applicable.

Fig. 2 is a sectional elevation showing one form of the invention in operative position, a

Fig. 3 is a sectional elevation similar to Fig. 2 but illustrating the method of assembly, I

Fig. 4 is another view similar to Fig. 2 but including a slight modification, and

Fig. 5 is a sectional elevation of a modified form of tube.

Referring first to Fig. 1 of the drawing, a valve push rod a, adapted to be reciprocated by a rocker one end of which is shown at b, passes through an opening 0 in the upper wall of a cam box or cam shaft housing 01 and also passes freely through a tubular passage e formed in a valve housing or cylinder head unit I supported by a cylinder block m having a flange n which is also apertured at o to provide passage for the push rod (1. Ordinarily, it is necessary to obtain exact axial alignment between the opening 0, the pas sage e and the aperture 0 so that a metallic tube can be fixed as by screw threading between the openings 0 and o to enclose that portion of the push rod which would otherwise be exposed. A0-

cording to the present invention, however, the need for alignment between the said apertures is obviated and space between the flange n and cam box d is adapted to be occupied by a sleeve g (Figs. 2 and 3) of India rubber or other flexible and resilient material which is so formedthat, as shown in Fig. 2 its walls are convex in vertical section giving it in effect a barrel shape which ensures that the sleeve can be compressed axially for positioning as hereinafter described, The sleeve ends are preferably formed with tapered spigots h adapted to engage in the sockets formed by the openings 0 and o, a heading 2 being formed adjacent each spigot end for the purpose of making close engagement with the edges of the sockets. The bead lips i also act as stiffening members and prevent the sleeve 9 passing too far into either socket formed by openings 0 or o. The shape of the sleeve g as shown; as well as its resilient character, also causes an end pressure to be exerted when in the operative position shown in Fig. 2 thereby ensuring a tight flt at the tapered spigots, this close fitting of the ends of the sleeve in the two walls being important in preventing any leakage of lubricating oil.

To insert the sleeve 9 in its operative position,

one end, preferably its lower end, is fitted into the socket c and the sleeve is buckled as shown to an exaggerated extent in Fig. 3 or otherwise partially collapsed to enable its other end to be sprung into position in the second socket 0. After the sleeve has been operatively positioned in this manner the push rod a is inserted and the device enables a mal-alignment, either intentional or accidental of the apertures c and o to exist thereby permitting a predetermined angularity of the push rod a in operative position.

In the form of construction shown in Fig. 4, the aperture 0 in the cylinder block flange is fitted with a metal or other ferrule is between which and the edge of the aperture 0 the spigot h at one end of the sleeve g is fitted, this arrangement improving the sealing at the upper end of the sleeve. The outer wall of the ferrule k is slightly coned in order to facilitate positioning of the spigot h. A similar ferrule may also be fitted in the aperture e. This form of construction is otherwise similar to that shown in Figs. 2 and 3. It is to be understood that the sleeve 9 can be applied to types of engine construction wherein a flange such as n does not exist, the upper spigot on the sleeve engaging directly in an aperture in a valve housing.

In order to increase the end pressure and, therefore, the tightness of the sealing at the ends between the cylinder block or of the sleeve g it can be formed by embodying a spring within the rubber, canvas or other material from which the sleeve is formed or alternatively, and as shown in Fig. 5, the sleeve constructed as shown in Figs. 2-4 can be used in conjunction with a helical spring I surrounding the exterior of the sleeve, and bearing against the beadings i, butin such an arrangement the sleeve itself mustxpossess: elasticity greater when the sleeve is used alone as in Figs. 2-4.

According to another form of the invention, the sleeve may take the form of a helical spring formed by a metal ribbon "with its coils over;- lapping so as completely to enclose thezpuslatrod cylinder headLand cam box, the ends of the spring'being'f'ormedbr' to be bent and one end por tion thereof sprung into position in one of said openings when the other end portion is seated in the other of said openings, and being sufficiently resilient in its longitudinal direction to enable it to be slightly compressed and shortened when mounted in said openings and thereby to exert longitudinally-directed resilient pressure on its seats in.-'said' openings: 7

'2; A housing for a valve-operating push rod in an internal combustion engine having relatively opposed housings which are provided with openingszthro sh which toi-passicomprising a sleeve composed of rubber,

flexible to enable it 15 the walls of which are somewhat convex in vertical section, having end portions constructed to i seat ade'tachably but with fluid-tight engagement provided with rigid or yieldabl'e; spigotnelementst;

so as to make sockets c and 0.

I claim:

I. Ahousingfor: a-valveq-operating; puslrmd-in anzinternal, combustion: engine:having-relatively opposed-housings which are? provided withi'opene ingsthrough which; the push rod: is! adapted; to pass; comprising a WhiflhziSi flexibleand longitudinally: resilient, the walls of which. are somewhat convex in vertical section, having end portions constructed to seat detachably but: with fiuide-tight engagement. within said openingsg-saidsleevebeingssuflicientlyliquid tight engagementiwi tlil-the sleeve composed of. material into position: in one of 1 said: openings.

said; openings and provided with outwardly-extending flanges adjacent to their ends,

said sleeve being sufiiciently flexible to enable it. to bebe'nt and;- on lenditportio r thereof; sprung when the" other endtpor-tiorr is seated-sin the other ofssaid: open-ings,. and being sufficiently resilient: inqitslongitudinal direction, to enablehit to be slightly compressed and-shortened when; mQuIltEdfiIhSflid openings and thereby to. exert longitudinallydirected" resilient pressure onits seatsrinr said, openings;

EDWARD the push rod is adapted- 

